The unlikely trio have released "Roll Me Up" in honor of the day associated with joint-rolling and smoking.

Country star Jamey Johnson joins them on the track, which begins with Nelson crooning, "Roll me up and smoke me when I die".

The track is available on Nelson's official website.

The 4/20 term was coined by a group of teenagers in San Rafael, California, in 1971 who pledged to meet at 4:20 p.m. every day to search for an abandoned cannabis crop. It has since evolved into code for pot-smoking in general.

April 20 has become a counterculture holiday in North America, where people gather to celebrate and consume cannabis.